The basics of industrial motor surge suppression

Surges can be very damaging to electronic equipment in various ways, making it important to take precautionary measures in order to avoid them.
By David Manney, L&S Electric August 18, 2017

Power and voltage surges only last for a millisecond, but they are very damaging to electronic equipment. These affect the electronic circuit by raising the voltage a few hundred or even a few thousand volts. Understanding the causes of power surges and how to reduce the risk helps save businesses from downtime and unexpected costs.

Image courtesy: CFE MediaCauses of surges

A power surge is caused by an event or issue within the facility or from outside of the facility. A higher percentage of power surges tend to occur as a result of problems within the facility, including within the electronic equipment itself. Both external and internal events leading to power surges cause significant problems.

A power surge occurs when there is a sudden change in the electrical conditions within the circuit. This change leads to larger amounts of energy released to the electrical system.

The following are two common causes of power surges within an industrial facility.

Internal surges

Internal surges occur from the day-to-day operation of many devices within the facility.

Those devices include:

  • Variable speed drives
  • Generators
  • Air conditioners
  • Electric motors
  • Elevators
  • Other electrical equipment.

Power surges also result from internal circuit breakers and fuses from within the equipment or at the electrical panel.

External surges

Weather events cause external power surges, such as lightning. That is by no means the only reason why they take place.

Other possibilities include:

  • Electrostatic discharge
  • Switching on or off capacitor banks
  • Power line disconnection and reconnection
  • Utility load switching
  • Turning transformers on and off
  • Poor quality within the distribution grid.

Protecting electrical equipment against power surges

Addressing the possibility of a power surge requires the necessary measures to reduce the risk. Even if unable to stop the surge itself, it is important to protect the electrical equipment from damage.

The following are some of the options for protecting against a power surge.

Separating cables: Avoid running low-voltage lines or communication lines parallel with power cables. Try to have them cross at a right angle if they must cross each other.

Grounding: A common ground should enter the building for all electrical systems. Those grounds should enter the building in proximity to each other.

Surge protection: Various options are available for surge protection. Install these options at the distribution panels. Connect surge protection to some of the larger electronic devices, such as large electric motors.

Surge arresters: Install surge arresters for any voltage application. Surge arresters protect electrical systems from large surges, such as those that occur from a lightning strike.

David Manney is marketing administrator at L&S Electric. This article originally appeared on Watts New, L&S Electric’s blog. L&S Electric is a CFE Media content partner. Edited by Carly Marchal, content specialist, CFE Media, cmarchal@cfemedia.com.